There's no set personality associated with it and most images do something different, so I'm curious what people individually imagine.

What if they lose their personality?

What's a shygal transformation? I assume I'm unfamiliar with the work that's from.

hypnohub.net/post/show/25...nde_hair-corruption-crown
hypnohub.net/post/show/25...and_after-belt-blonde_hai
hypnohub.net/post/show/28...s-corruption-dazed-drool-

Those are probably what they're referring to.
I feel that, often, the transformed become cute and bubbly, and often have sexier outfits that before, but some other times (like in the Sleepymaid pic), they seem happy to be covered in clothes.

Probably get Shy Guy traits (shyness, wanting to be hidden), and cute/airhead traits because, y'know, porn.

Ah thank you

I think they'd cluster together, looking for strength in numbers, and they'd try to get each other to do things rather than being brave enough to do it themselves.

For example, maybe four of them see a hot guy, and push one of them to flirt with him. If things seem to be going well, the other three slowly join in, wanting a piece. They get him alone, and when they see his cock, the process repeats. They get scared, one of them is convinced to go first, she enjoys it, they get jealous and join in.